1. Field of the Invention
The present invention is directed in general to amplified speakers of the type where the speaker and the amplifier associated therewith are mounted within the same assembly, and in particular to an amplified speaker assembly and method which allow each amplified speaker assembly to be individually addressed.
2. Discussion of the Background
Amplified speakers are generally employed in situations where a local amplifier is not required, or is not available. For example, amplified speakers are commonly employed in public announcement systems and various telephone applications where use of a local amplifier to drive multiple speakers in remote locations is impractical and virtually impossible. By contrast, non-amplified speakers are often used in home audio systems where, for example, a local amplifier drives a multi-speaker surround-sound audio system.
Conventional amplified speakers are described in, for example, U.S. Pat. No. 5,164,991 to Johnson et al. where an example of a typical amplified speaker includes an electroacoustic speaker having an amplifier section mounted thereon. The amplifier section may be provided as an encapsulated unit or it may simply consist of a printed circuit board with the necessary electronics mounted on and connected to input terminals of the speaker. In those applications where the speaker is mounted in an enclosure, such a disk speakers of the type associated with telephone systems, the amplifier section may be mounted within the speaker enclosure in any convenient manner. With regard to horn speakers and other speakers having a housing or outer casing (which often find application in public announcement systems indoor and/or outdoor), the amplifier section may be mounted within the speaker casing, to provide for weatherproofing of the electronics or to render the speaker explosion-proof.
One of the drawbacks associated with public announcement systems is lack of individual addressability of the amplified speakers associated with the system. That is, while public announcement systems are well suited for broadcast operation of a message from a single source or multiple amplified speakers, such systems are incapable of broadcasting messages from different sources in different zones of the systems.
Paging systems, of the type typically employed in telephony where each telephone device has an amplified speaker, allow for the capability of sending specific paging signals from one telephone device to another, or to a group of, telephone device(s) (audio paging output device(s)) disposed within a certain zone of the system. U.S. Pat. No. 5,740,235 to Lester et al. discloses a two-way hardwired paging system controller which is accessible from a plurality of input devices, and is user programmable to respond to signaling activity sourced from the input devices to establish a paging connection and perform paging with respect to a selected paging zone served by the system. The paging system controller includes a plurality of input ports, output ports and a bidirectional signal interface unit which provides a page/tone signal path for page/tone signals source from input ports to audio paging output devices of a paging speaker/amplifier subsystem that are coupled to the selected output ports. The signal interface unit also couples talkback tone signals to selected input port connections. The output paging signal functions include transmission of audio tone and voice paging signals via an audio signal path from a paging source to one or more controllably energized paging loudspeakers. One of the drawbacks of such a system is that it requires a sophisticated central paging system controller to process paging requests and to route such requests to appropriate audio paging output devices. Only those signal sources connected to the input ports of the central paging controller may send paging signals to audio paging output devices (which also must be connected to the central paging controller). Another drawback of such a system, is the hardwired configuration which may be impractical or physically impossible for some system configurations. Yet another drawback of such a system is that it does not provide for remote volume control of audio paging output devices associated therewith.
U.S. Pat. No. 6,226,370 to Shih discloses a telephone pager and intercom system which is connectable to residential DTMF telephone lines, and includes a plurality of pager devices connected to phone lines between the tip and ring wires for each telephone device. Each pager device is individually addressable by means of an identification circuit provided therein. During operation, a person using a telephone keypad may enter a DTMF activation sequence which includes a header, a pager access (pager identification PID which enables a particular pager) and a signal identification (SID which defines which signal is to be produced on the selected pager). An “Intercom Assist” function may be provided in a pager to allow the phone connected through the pager to be put automatically on-hook when intercom usage is detected. “Intercom Assist” allows a local phone line loop to carry DTMF sequences for activating pagers and to carry voice signals for the intercom function to the phone associated with the pager. While the telephone pager system describe in U.S. Pat. No. 6,226,370 to Shih avoids the use of central paging system, this system has very limited capability in that it is confined to telephone devices connected to a single local telephone loop, and (like the system disclosed in U.S. Pat. No. 5,740,235 to Lester et al.) it is hardwired. Also, like the system disclosed in U.S. Pat. No. 5,740,235 to Lester et al., telephone pager and intercom system described in U.S. Pat. No. 6,226,370 to Shih lacks remote volume control capability. Furthermore, Shih does not provide for voice annunciation.